Change undefined to null

Author: dy

src/traces/pointcloud/attributes.js

@@ -75,7 +75,7 @@ module.exports = {
         },
         blend: {
             valType: 'boolean',
-            dflt: undefined,
+            dflt: null,
             role: 'style',
             description: [
                 'Determines if colors are blended together for a translucency effect',

src/traces/pointcloud/convert.js

@@ -178,7 +178,7 @@ proto.updateFast = function(options) {
     // detect blending from the number of points, if undefined
     // because large data with blending hits performance
     var blend = options.marker.blend;
-    if(blend === undefined) {
+    if(blend === null) {
         var maxPoints = 100;
         blend = x.length < maxPoints || y.length < maxPoints;
     }